Pressure relief arrangement for open surgery insufflation system

ABSTRACT

A surgical humidification system includes a source of gas flow and a humidifier that receives the gas flow and outputs a humidified gas to a delivery conduit. The delivery conduit has an outlet and a suitable interface, such as a diffuser, is connected to the outlet. The interface can be positioned near or within an open surgical cavity of a patient to supply the humidified gas to the cavity. The system also includes a pressure relief arrangement that operates to relieve pressure from the system above a normal operating pressure. The pressure relief arrangement can be located in a non-sterile portion of the system, such as upstream from the humidifier, for example.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Field

This disclosure relates generally to open surgery insufflation systems,and more particularly to humidified insufflation systems for opensurgery.

Description of Related Art

Insufflation gases can be used in surgery for a variety of purposes. Inopen surgery, gas can be insufflated into a body cavity for de-airing,as in cardiac or thoracic surgery, for example. The insufflation gas canbe inert or non-toxic, such as air or carbon dioxide (CO2). Otherinsufflation gases that have been proposed are nitrogen gas (N2),nitrogen dioxide NO2, Argon (Ar) and Helium (He). Medical grade CO2 canbe supplied in cylinders and delivered to a patient at room temperature(e.g., between about 19 and 21 degrees Celsius), with a relativehumidity approaching 0%. This gas is colder and drier than theenvironment inside the patient (e.g., about 37 degrees Celsius and arelative humidity of about 100%, respectively). Temperature and humidityof an insufflation gas can be adjusted to more closely approximate theenvironment inside the patient prior to delivery. Heating andhumidifying the insufflation gas can decrease cellular damage ordesiccation, limit adhesion formation, or reduce other deleteriouseffects. Although open surgery humidified insufflation systems exist,there remains room for improvement to, for example, increase theperformance or reliability of the system.

SUMMARY

The systems, methods and devices described herein have innovativeaspects, no single one of which is indispensable or solely responsiblefor their desirable attributes. Without limiting the scope of theclaims, some of the advantageous features will now be summarized.

An aspect involves an open surgical insufflation system. The systemcomprises a gas source for providing a constant flow of insufflationgas. A humidifier receives the flow of insufflation gas from the gassource and warms and humidifies the flow of insufflation gas. A gasdiffuser dispenses the warmed and humidified flow of insufflation gasfrom the humidifier into an open surgical cavity in direct contact withan external atmosphere to create an insufflation gas environment in theopen surgical cavity. A pressure relief arrangement is activated inresponse to a system pressure above a threshold pressure and operates toreduce the system pressure when activated.

In some configurations, the pressure relief arrangement is locatedbetween the gas source and the humidifier.

In some configurations, the pressure relief arrangement is locatedupstream from the humidifier relative to a direction of the flow ofinsufflation gas within the system.

In some configurations, the pressure relief arrangement is locateddownstream from the humidifier relative to a direction of the flow ofinsufflation gas within the system.

In some configurations, the threshold pressure is no greater than about12 psi.

In some configurations, the threshold pressure is no greater than about9.5 psi.

In some configurations, the threshold pressure is no greater than about5 psi.

In some configurations, the threshold pressure is between about 2 psiand about 9.5 psi.

In some configurations, the threshold pressure is between about 3 psiand about 5 psi.

In some configurations, the gas source comprises a gas bottle, apressure regulator and a flow meter. In some configurations, the flowmeter is adjustable and permits a flow rate of the flow of insufflationgas to be adjusted to between about 5 L/min and about 15 L/min. In someconfigurations, the flow rate can be adjusted to about 10 L/min.

In some configurations, the gas diffuser is constructed from a foam orfoam-like material.

In some configurations the pressure relief arrangement may comprise apressure relief valve.

In some configurations the pressure relief arrangement may comprise aprotective shroud or cover around the pressure relief valve.

An aspect involves a method of providing insufflation gas therapy in anopen surgical procedure. The method comprises providing a flow of aninsufflation gas from a gas source. The flow of insufflation gas ispassed through a humidification chamber to warm and humidify the flow ofinsufflation gas. The gas is diffused from a gas diffuser to within asurgical cavity that is open to the atmosphere to create an insufflationgas environment within the surgical cavity. Pressure within a systemcomprising the gas source, humidification chamber and the gas diffuseris relieved through a pressure relief valve that is separate from thegas diffuser in response to an increase in pressure within the systemabove a threshold pressure.

In some configurations, the pressure relief valve is located between thegas source and the humidification chamber.

In some configurations, the pressure relief valve is located upstreamfrom the humidification chamber relative to a direction of the flow ofinsufflation gas within the system.

In some configurations, the pressure relief valve is located downstreamfrom the humidification chamber relative to a direction of the flow ofinsufflation gas within the system.

In some configurations, the threshold pressure is no greater than about12 psi.

In some configurations, the threshold pressure is no greater than about9.5 psi.

In some configurations, the threshold pressure is no greater than about5 psi.

In some configurations, the threshold pressure is between about 2 psiand about 9.5 psi.

In some configurations, the threshold pressure is between about 3 psiand about 5 psi.

In some configurations, the gas source comprises a gas bottle, apressure regulator and a flow meter. In some configurations, the flowmeter is adjusted so that a flow rate of the flow of insufflation gas isbetween about 5 L/min and about 15 L/min. In some configurations, theflow meter is adjusted so that the flow rate is about 10 L/min.

In some configurations, the gas diffuser is constructed from a foam orfoam-like material.

An aspect involves a method of assembling an open surgical insufflationsystem. The method comprises connecting a gas source to a humidifier,the gas source configured to supply a constant flow of an insufflationgas and the humidifier configured to receive the flow of insufflationgas and warm and humidify the insufflation gas. A gas diffuser isconnected to the humidifier, the gas diffuser configured to dispense theflow of insufflation gas to an open surgical cavity of a patient. Apressure relief valve is connected to the system, the pressure reliefvalve configured to reduce pressure within the system when the pressurereaches a threshold pressure.

In some configurations, the connecting of the pressure relief valvecomprises connecting the pressure relief valve between the gas sourceand the humidifier.

In some configurations, the connecting of the pressure relief valvecomprises connecting pressure relief valve at a location upstream fromthe humidifier relative to a direction of the flow of insufflation gaswithin the system.

In some configurations, the connecting of the pressure relief valvecomprises connecting pressure relief valve at a location downstream fromthe humidifier relative to a direction of the flow of insufflation gaswithin the system.

In some configurations, the threshold pressure is no greater than about12 psi.

In some configurations, the threshold pressure is no greater than about9.5 psi.

In some configurations, the threshold pressure is no greater than about5 psi.

In some configurations, the threshold pressure is between about 2 psiand about 9.5 psi.

In some configurations, the threshold pressure is between about 3 psiand about 5 psi.

In some configurations, the gas source comprises a gas bottle, apressure regulator and a flow meter and the method comprises connectingthe humidifier to the flow meter.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers can be reused to indicategeneral correspondence between reference elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

FIG. 1 illustrates an example open surgery insufflation system fordelivering temperature-controlled and humidity-controlled insufflationgas to an open surgical site of a patient. The system includes apressure relief valve positioned upstream from a humidifier of thesystem.

FIG. 2 illustrates the system of FIG. 1 with the humidifier and gasdiffuser of the system shown in greater detail.

FIG. 3 illustrates a modification of the system of FIG. 1, with thepressure relief valve positioned downstream from the humidifier.

FIGS. 4a and 4b illustrate a modification of the system of FIG. 1, withthe pressure relief valve provided with a protective shroud.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Described herein are methods and systems that relieve system pressure orlimit the maximum pressure in an open loop or open insufflation systemfor use in open or direct access surgical procedures. It will beunderstood that although much of the description herein is in thecontext of open surgery, one or more features of the present disclosurecan also be implemented in other scenarios where it is desirable tolimit the output pressure of a gas, such as respiratory applications.

Insufflation gases can be used in a variety of surgical procedures. Inopen surgery, insufflation gases can be used in a body cavity forde-airing, which can decrease the risk of air embolism or, possibly,decrease the risk of infection of the surgical wound. In open surgicalapplications, the insufflation system is an open loop system thatprovides a generally constant flow of insufflation gas as a desired flowrate over a desirable period of time, which can encompass a portion orthe entirety of the surgical procedure. Such an open loop system is incontrast to the (essentially) closed loop or feedback insufflationsystems used in minimally invasive surgery, in which insufflation gas isprovided discontinuously or on demand to maintain a relatively lowpressure (e.g., 0.3 psi, 2 kPa) within the essentially sealed bodycavity.

It has been discovered by the present inventor that, althoughinsufflation systems for use in open surgery are open loop gas deliverysystems, which deliver insufflation gas to the atmosphere, occlusion ofthe system can occur during normal or routine operation. Occlusion ofthe system can cause a rise in system pressure and, possibly, failure ofor damage to components of the system. This failure or damage can causea temporary or, in some cases, a complete interruption in theinsufflation therapy. Thus, the present inventor has discovered that itcan be desirable to provide for pressure relief in an open loopinsufflation system.

In some configurations, the open loop surgery insufflation systemincorporates a humidifier to warm and humidify the deliveredinsufflation gas. Body cavity environments can include cells that aresusceptible to damage when exposed to relatively dry and cold gases.Insufflation gases can be relatively cold and dry and may cause damageto cells, damage that can be reduced or avoided through humidifying andwarming the insufflation gas. Warming and humidifying the insufflationgas can reduce or prevent cellular desiccation. This can have a positiveeffect on post-operative pain that not only increases quality of carebut reduces recovery time and increase department throughput. Warmingand humidifying insufflation gases may reduce intra-operativehypothermia, reduce post-operative pain, and improve post-operativerecovery.

Some embodiments described herein provide for a humidification systemthat is configured to deliver warm, humidified gas to a patientundergoing a surgical procedure. The gas is passed through a waterchamber which is filled with water that is heated using a heater plate.Water evaporates in the chamber and combines with the gas which flowsover it, thereby heating and/or humidifying the gas. The temperature ofthe gas can be maintained as it travels along a heated tube to an outletport for delivery to the patient. The humidification system can monitorthe temperature and flow rate of the gas at a chamber outlet, andcontrol an amount of electrical power delivered to the heater plate toprovide a gas having a desired temperature and humidity. Thus, surgicalgas from a gas source (e.g., a gas bottle, wall source or the like) canbe humidified and heated and delivered to the patient, enabling thetargeted area to remain moist and warm.

Some embodiments described herein provide for a surgical humidificationsystem that includes a humidifier control system configured to determinea mode of operation, a mode of control, a heater plate set point, or anycombination of these. The humidifier control system can base thisdetermination at least in part on feedback from components of thehumidification system. The components of the humidification system canprovide feedback through sensors or other electrical components, andfeedback can include, for example, outlet gas temperature, heater platetemperature, heater plate power, gas flow rate, user input through userinterface elements, duration of operation, and the like. Someembodiments of the humidifier control system can improve efficiency ofthe humidification system, provide an output gas with relativelyconsistent humidity and temperature, and provide greater control overtemperature and humidity of the gas compared to control systems that donot incorporate system component feedback. The humidifier control systemcan provide at least some of these improvements through modulesconfigured to process system component feedback and adjust outputsettings according to a control loop feedback mechanism. If provided,the humidifier can be controlled in any suitable manner, such as using aportion or an entirety of the control systems and methods disclosed inU.S. Provisional Patent Application No. 61/699,773, filed Sep. 11, 2012and entitled SURGICAL HUMIDIFIER CONTROL.

FIG. 1 illustrates an example open surgery insufflation system 10 fordelivering an insufflation gas to a patient 12 and, in particular, to anopen surgical site of the patient 12, which can be, for example andwithout limitation, an area, cavity or wound (collectively referred toas a “cavity”). The open surgery insufflation system 10 comprises a gassource 14 for supplying a flow of insufflation gas. The insufflation gascan be any suitable gas for the desired purpose; however, in someconfigurations the insufflation gas is carbon dioxide (CO2). Asdescribed above, CO2 is often used as a surgical insufflation gas and iswell-suited for open surgery insufflation because CO2 is heavier thanair and tends to displace air in an open surgical cavity.

The gas source 14 can be of any suitable arrangement to deliver asuitable flow of insufflation gas, which in some configurations is aconstant flow of insufflation gas. In some configurations, the gassource 14 comprises a gas bottle 16 filled with a compressedinsufflation gas, such as CO2. However, in other configurations, theinsufflation gas could be supplied by another gas supply, such as a wallsupply (i.e., gas supplied via appropriate conduit from a remotereservoir) for example and without limitation. The gas source 14 canalso comprise a pressure regulator 20 if necessary or desirable toregulate the pressure of the flow of insufflation gas provided by thegas bottle 16 or other gas supply. In some configurations, the gasbottle 16 contains insufflation gas (e.g., CO2) that is pressurized to arelatively high pressure (e.g., about 5,000 kPa or about 725 psi). Thepressure regulator 20 can reduce the pressure of gas supplied by the gasbottle 16 to a pressure more suitable for use by the open surgeryinsufflation system 10, such as about 400 kPa (about 58 psi), forexample. It is possible to construct a pressure regulator 20 that couldfurther reduce the pressure of gas supplied by the gas bottle 16;however, such a regulator would be larger and/or more complicated andmay not be practical for use in a surgical setting.

In some configurations, the gas source 14 comprises a flow regulator orflow meter 22 for regulating the flow rate of the flow of insufflationgas from the gas bottle 16 or other gas supply. The flow meter 22 can beany suitable type, such as a flow meter commonly used to regulate theflow rate of medical gases (e.g., respiratory gases). The flow meter 22can be adjustable to permit adjustment of the gas flow rate. The flowmeter 22 can permit adjustment of the flow rate within any suitablerange. In some configurations, the flow meter 22 can permit adjustmentof the flow rate up to about 25 liters/minute (L/min). In someconfigurations, the flow meter 22 can permit adjustment of the flow rateto between about 1-2 L/min and about 25 L/min. More particularly, theflow meter 22 can permit adjustment of the flow rate between about 5L/min to about 15 L/min. Even more particularly, the flow meter 22 canprovide a flow rate of about 10 L/min. In some configurations, arelatively low flow rate is desired and, in some such configurations,the insufflation gas can be shielded from evacuation from the surgicalsite, such as with a barrier, and/or the insufflation gas level can bemeasured at the surgical site. If the insufflation gas level ismeasured, feedback control of the flow rate can be utilized. However,other suitable flow rates can also be used, which may greater than 25L/min.

In the illustrated configuration, the gas bottle 16 (or other gassupply), pressure regulator 20 and flow meter 22 are separate from oneanother and coupled by suitable conduits 24. However, in otherconfigurations, one or more of these components could be combined in anintegrated unit. Other suitable arrangements are also possible.

The open surgery insufflation system 10 can also include a humidifier30, which receives a flow of insufflation gas from the gas source 14 andoutputs a warmed and humidified flow of insufflation gas. The humidifier30 can be of any suitable arrangement, such as the humidifier 30described below with reference to FIG. 2 or any other suitablearrangement.

The open surgery insufflation system 10 can also comprise an outlet 32for dispensing the flow of insufflation gas. The outlet 32 can be of anysuitable arrangement to deliver the flow of insufflation gas to the opensurgical cavity of the patient 12. In some configurations, the outlet 32is configured to disperse the flow of insufflation gas as it exits theoutlet 32. In particular, the outlet 32 can comprise a gas diffuser ofany suitable arrangement. The outlet 32 (e.g., diffuser, nozzle or otherarrangement) can be referred to generally as an interface or patientinterface.

The open surgery insufflation system 10 also comprises a pressure reliefarrangement, which can comprise a pressure relief valve or check valve40 (referred to hereinafter as a “pressure relief valve”). The pressurerelief valve 40 can be configured to relieve pressure within the opensurgery insufflation system 10 in response to system pressure above athreshold pressure level. The pressure relief valve 40 can be of anysuitable type for use in a medical fluid system, such as aball-and-spring valve, a diaphragm valve, a leaflet valve, etc. In someconfigurations, the threshold pressure level can be set to be slightlyor significantly higher than system pressures that are expected to occurduring normal use of the open surgery insufflation system 10, which caninclude system pressures that occur as a result of foreseeable, butless-than-ideal use of the system 10. In response to systems pressuresabove a threshold, the pressure relief valve 40 can open to ventpressure from the open surgery insufflation system 10, such as to theatmosphere, and reduce the system pressure. Such an arrangement canreduce the incident of or prevent failure of a system component, such asconnections (e.g., taper, luer or barb connections) between componentsof the system 10 or, in some cases, larger system components (e.g., thehumidifier 30).

FIG. 2 illustrates the open surgery insufflation system 10 with anexample surgical humidification system 100 for delivering temperature-and humidity-controlled gas to a patient 102 shown in greater detail. Asdescribed above, open surgery insufflation system 10 can comprise ahumidifier 30, which can incorporate a humidifier control system 50. Thehumidifier 30 is connected to the gas source 14 through a supply conduit52. The humidifier 30 delivers humidified gas to the patient 12 througha patient conduit 54. The conduits 52, 54 can be made of any suitablematerial, such as flexible plastic tubing, for example.

The humidifier 30 receives gas from the gas source 14 through the supplyconduit 52. The gas can be filtered through a filter 56 and delivered tothe humidifier 30 through a humidifier inlet 60. The filter 56 can bepositioned at any suitable location within the system 10, such asupstream from the humidifier 30, as shown, or downstream from thehumidifier 30. The gas is humidified as it passes through a humidifyingchamber 62, which is effectively a water bath, and the gas flows outthrough a humidifier outlet 64 and into the patient conduit 54. The gasthen moves through the patient conduit 54 to the patient 12. In someconfigurations, a filter can be disposed between the humidifier outlet64 and the patient 12.

The humidifier 30 comprises a body or base 66 with which thehumidification chamber 62 can be removably engaged. In someconfigurations, the humidification chamber 62 has a metal base 70 and isadapted to hold a volume of water 72, which can be heated by a heaterplate 74. The heater plate 74 can be in thermal contact with the metalbase 70 of the humidification chamber 62. Providing power to the heaterplate 74 can cause heat to flow from the heater plate 74 to the water 72through the metal base 70. As the water 72 within the humidificationchamber 62 is heated it can evaporate and the evaporated water can mixwith gases flowing through the humidification chamber 62 from the filter56 and gas source 14. Accordingly, the humidified gases leave thehumidification chamber 62 via outlet 64 and are passed to the patient 12via the patient conduit 54 preferably to the surgical site to insufflatethe surgical site.

In some configurations, the humidifier 30 includes the humidifiercontrol system 50 configured to control a temperature and/or humidity ofthe gas being delivered to the patient 12. The humidifier control system50 can be configured to regulate an amount of humidity supplied to thegases by controlling an electrical power supplied to the heater base 74.The humidifier control system 50 can control operation of the humidifier30 in accordance with instructions set in software and in response tosystem inputs. System inputs can include a heater plate sensor 76, anoutlet chamber temperature sensor 80, and a chamber outlet flow probe82. For example, the humidifier control system 50 can receivetemperature information from the heater plate sensor 76 which it can useas an input to a control module used to control the power or temperatureset point of the heater plate 74. The humidifier control system 50 canbe provided with inputs of temperature and/or flow rates of the gases.For example, the chamber outlet temperature sensor 80 can be provided toindicate to the humidifier control system 50 the temperature of thehumidified gas as it leaves the outlet 64 of the humidification chamber62. The temperature of the gases exiting the chamber can be measuredusing any suitable temperature sensor 80, such as a wire-basedtemperature sensor. The chamber outlet flow probe 82 can be provided toindicate to the humidifier control system 50 the flow rate of thehumidified gas. The flow rate of the gases through the chamber 62 can bemeasured using any suitable flow probe 82, such as a hot wireanemometer. In some embodiments, the temperature sensor 80 and flowprobe 82 are in the same sensor housing. The temperature sensor 80 andflow probe 82 can be connected to the humidifier 30 via connector 84.Additional sensors may be incorporated into the open surgeryinsufflation system 10, for example, for sensing parameters at thepatient end of the patient conduit 54.

The humidifier control system 50 can be in communication with the heaterplate 74 such that the humidifier control system 50 can control a powerdelivered to the heater plate 74 and/or control a temperature set pointof the heater plate 74. The humidifier control system 50 can determinean amount of power to deliver to the heater plate 74, or a heater plateset point, based at least in part on a flow condition, an operationmode, a flow reading, an outlet temperature reading, a heater platesensor reading, or any combination of these or other factors.

The open surgery insufflation system 10 can include a conduit heatingwire 86 configured to provide heat to the gases traveling along thepatient conduit 54. Gases leaving the outlet 64 of the humidificationchamber 62 can have a high relative humidity (e.g., about 100%). As thegases travel along the patient conduit 54 there is a chance that watervapor may condense on the conduit wall, reducing the water content ofthe gases. To reduce condensation of the gases within the conduit 54,the conduit heating wire 86 can be provided within, throughout, and/oraround the patient conduit 54. Power can be supplied to the conduitheating wire 86 from the humidifier 30 and can be controlled through thehumidifier control system 50. In some configurations, the heating wire86 is configured to maintain the temperature of the gas flowing throughthe patient conduit 54. In some configurations, the conduit heating wire86 can provide additional heating of the gas to elevate the gasestemperature to maintain the humidity generated by the heated water bathin the humidifier 30.

FIG. 2 also illustrates an example of an outlet 32, which can be in theform of a surgical site insufflation gas interface 32 for delivering thepreferably warmed and humidified flow of insufflation gas from thepatient conduit 54 to the surgical site (e.g., surgical cavity 92). Thegas interface 32 can be of any suitable arrangement for delivering aflow of insufflation gas at a sufficient flow rate to create at least apartial protective environment or insufflation gas environment 94 near,at or within the surgical cavity 92. In some configurations, the gasinterface 32 (in combination with a suitable gas source 14 and optionalhumidifier 30) can deliver a sufficient amount of insufflation gas tomaintain an insufflation gas concentration (e.g., CO2 concentration) ofat least about 80%, or at least about 90%, within a substantial portionor an entirety of the surgical cavity 92. In some configurations, thegas interface 32 can deliver a sufficient amount of insufflation gas tomaintain an insufflation gas concentration of between about 80% andabout 99%, or between about 90% and about 99%, within a substantialportion or an entirety of the surgical cavity 92. In someconfigurations, the gas interface 32 (in combination with a suitable gassource 14 and optional humidifier 30) can deliver up to about 25 L/min.In some configurations, the gas interface 32 can deliver between about1-2 L/min and about 25 L/min. In some configurations, the gas interface32 can deliver between about 5 L/min and about 15 L/min, or betweenabout 8 L/min to about 12 L/min. In some configurations, the gasinterface 32 can deliver about 10 L/min.

Preferably, the gas interface 32 can deliver the insufflation gas in amanner that minimizes or eliminates any deleterious effects on thesurrounding tissue. That is, preferably the gas interface 32 does notprovide a jet of insufflation gas, but disperses the insufflation gasover a larger area or through multiple outlets or ports and, in at leastsome cases, avoids creating turbulence. In some configurations, the gasinterface comprises a gas diffuser 96 for dispersing the insufflationgas from the system 10 in a diffused manner. The gas diffuser 96 can beof any suitable arrangement. In some configurations, the gas diffuser 96is coupled to the patient conduit 54 by a conduit or tube 100. The tube100 preferably is secured to the patient conduit 54 by a suitableconnector 102, such as a luer lock connector.

In some configurations, the gas diffuser 96 comprises a porous body,which includes a large number of ports, flow paths or cavities thatpermit the insufflation gas to pass from the tube 100 to the atmosphereoutside of the gas diffuser 96. The flow paths or cavities can beinherent in the material(s) used to construct the gas diffuser 96 or canbe created within a base material(s). In some configurations, the gasdiffuser 96 is constructed from a porous material, such as foam orfoam-like material or sponge or sponge-like material. In someconfigurations, the gas diffuser 96 can be constructed from ahydrophobic material. Suitable gas diffusers 96 are marketed by CardiaInnovation AB of Stockholm, Sweden (the Vita diffuser) and Temed ofBosham, England. Examples of gas diffuser are disclosed in U.S. Pat.Nos. 6,494,858 and 6,994,685, the entireties of which are incorporatedby reference herein. Other suitable gas diffusers 96 could also be used,such as perforated tubes or catheters or other perforated dispensers,for example and without limitation.

In some configurations, the tube 100 can include features to inhibit orprevent accidental occlusion, such as internal support ribs, forexample. In some configurations, the tube 100 can be deformable and canbe configured to hold its shape once deformed. For example, one or moreof the internal ribs, a wall of the tube 100 or another portion of thetube could incorporated a malleable material that would hold the tube100 in a desired shape once deformed. Thus, the tube 100 could be bentto allow the gas diffuser 96 to be positioned within the surgical cavity92 and a portion of the tube 100 to be placed in contact with thepatient 12 at a location adjacent to the surgical cavity 92. If desired,the tube 100 can be secured in place.

As described above, the open surgery insufflation system 10 preferablyincludes a pressure relief arrangement, which can be a pressure reliefvalve 40. The pressure relief valve 40 can relieve or vent pressure fromwithin the system 10 if the system pressure reaches or exceeds athreshold pressure. The system 10 could reach or exceed the thresholdpressure as a result of the partial or complete occlusion of a passagewithin the system 10, such as within the supply conduit 52, patientconduit 54, tube 100 or gas diffuser 96, for example and withoutlimitation. The pressure relief valve 40 can be positioned at anysuitable location within the system 10. In some configurations, thepressure relief valve 40 is located in a non-sterile portion of the opensurgery insufflation system 10 when the system 10 is in normal use undernormal circumstances. For example, a portion of the system 10 from thegas source 14 up to and including the humidifier 30 can be non-sterilein normal use. A sterile portion of the system 10 can include the gasdiffuser 96, tube 100 and connector 102, which can be an integratedassembly in some cases. The patient conduit 54 can be sterile,non-sterile or can have portions that are within the sterile field andportions that are within the non-sterile field.

Positioning the pressure relief valve 40 in the non-sterile field orwithin a non-sterile area is advantageous because the pressure reliefvalve 40 can be re-used. In some configurations, as illustrated in FIG.2, the pressure relief valve 40 can be positioned upstream of thehumidifier 30 relative to a direction of the gas flow. In someconfigurations, the pressure relief valve 40 can be positioned betweenthe gas source 14 and the humidifier 30. In particular, the pressurerelief valve 40 can be positioned between the flow meter 22 and thehumidifier 30. In some configurations, the pressure relief valve 40 canbe positioned along or integrated into the supply conduit 52. Forexample, the pressure relief valve 40 can be coupled to a pair ofconduit portions of the supply conduit 52 by a tee connection, such asan NPT threaded ¼ inch tee connection, for example and withoutlimitation.

In other configurations, the pressure relief valve 40 can be positioneddownstream of the humidifier 30 and/or within a sterile portion of theopen surgery insufflation system 10. One such optional arrangement isillustrated in FIG. 3. In such arrangements, the pressure relief valve40 can be a consumable or disposable component of the system 10. In someconfigurations, the pressure relief valve 40 can be positioned betweenthe humidifier 30 and the diffuser 32. In some such configurations, thepressure relief valve 40 can be positioned along, or integrated into,the patient conduit 54 (e.g., as described above with respect to thesupply conduit 52), between the patient conduit 54 and the diffuser 32,or integrated within the diffuser 32.

In use, the components of the system 10 can be assembled, if necessary.Supply of insufflation gas from the gas source 14 can be initiated, suchas by opening the valve of the gas bottle 16 or other gas supply, forexample. If necessary, the flow meter 22 can be adjusted to achieve adesirable flow rate of the insufflation gas. If present, the humidifier30 can be turned on and adjusted to warm and humidify the insufflationgas to a desirable level. The gas diffuser 96 of the gas interface 32can be positioned within the surgical cavity 92 of the patient 12 tocreate an insufflation gas environment 94, which can be maintainedthroughout completion of the surgical procedure. In the event of a risein system pressure above a threshold pressure, the pressure relief valve40 can activate, open or vent the flow of insufflation gas to reduce thesystem pressure.

It has been unexpectedly discovered by the present inventor that,although the open surgery insufflation system 10 is an open system thatdispenses insufflation gas to a generally open atmosphere that normallyresults in a low system pressure, occlusions can occur within the system10 during normal, or at least foreseeable, use that can cause asignificant rise in the system pressure. In some cases, the rise insystem pressure can be sufficient, in the absence of a pressure reliefarrangement 40, to cause temporary or permanent damage to components ofthe system 10. For example, elevated system pressure can cause thedisconnection of components of the system 10, such as the supply conduit52 with the flow meter 22, for example, which may be a hose and barbconnection. In some cases, the disconnection can be of a luer lockconnection, taper connection or other type of connection. In some cases,elevated system pressure can cause permanent damage, such as damage tothe humidifier 30 (e.g., the humidifying chamber 62), for example.Damage to the system 10, temporary or permanent, can cause aninterruption or cessation of the insufflation therapy, which isundesirable at the least.

It has been discovered that some causes for occlusion of the system 10include, for example and without limitation, manipulation of the gasdiffuser 96 (e.g., depression of the diffuser material during placementor to evacuate fluid build-up in the diffuser material), manipulation(e.g., bending) of the tube 100, submersion of the gas diffuser 96 influid, and the gas diffuser 96 being adjacent to or surrounded by anobject that partially or completely blocks flow, such as a semi-solid ora solid material (e.g., gauze, organs), for example and withoutlimitation. In some cases, these actions or activities result in modestincreases of the system pressure that do not pose a significant risk ofdamage or interruption of the insufflation therapy. However, in somecases, such actions or activities could result in significant increasesin system pressure that could create a significant risk of damage orinterruption of the insufflation therapy.

The present inventor has investigated the system pressure increasescaused by these and similar actions or activities, as well as the systempressures that could cause damage to the system 10. For example, theconnection strength of the various connections between components andconduits of the system 10 was evaluated. As a result, it was determinedthat a preferred pressure relief valve 40 should open or vent systempressure at a threshold pressure of no more than about 83 kPa (12 poundsper square inch (psi)). In some configurations, it is preferable for thethreshold pressure for opening or venting of the pressure relief valve40 to be no more than about 65.5 kPa (9.5 psi). In some configurations,it is desirable for the threshold pressure for opening or venting of thepressure relief valve 40 to be no more than about 34.5 kPa (5 psi). Suchopening or venting threshold have been determined to be suitable toreduce or eliminate the risk of damage to the system 10 or interruptionof the insufflation therapy.

In some configurations, it is desirable to avoid opening or venting thepressure relief valve 40 in response to elevations in system pressurethat are not likely to be harmful to components of the system 10. Thus,in some configurations, it is desirable to configure the pressure reliefvalve 40 to remain closed or not vent in response to system pressurelower than about 14 kPa (2 psi). In some configurations, it is desirableto configure the pressure relief valve 40 to remain closed or not ventin response to system pressure lower than about 24 kPa (3.5 psi). Thus,in some configurations, it is desirable to configure the pressure reliefvalve 40 to have an opening or venting threshold pressure of betweenabout 14 kPa (2 psi) to about 83 kPa (12 psi), or between about 14 kPa(2 psi) to about 34.5 kPa (5 psi). In other configurations, it isdesirable to configure the pressure relief valve 40 to have an openingor venting threshold pressure of between about 21 kPa (3 psi) to about83 kPa (12 psi), or between about 21 kPa (3 psi) to about 65.5 kPa (9.5psi). Any values or ranges within the above-recited ranges are alsocontemplated. In other configurations, or other applications, thepressure relief valve 40 may be configured to have a higher activation,opening or venting pressure threshold. In some configurations, thepressure threshold of the pressure relief valve 40 is fixed and/orpreset. In other configurations, the pressure threshold could beadjustable, such as adjustable within one or more of the rangesidentified herein.

With additional reference to FIGS. 4a and 4b , the pressure relief valve40 may be provided with a protective shroud 110 which at least partiallyencloses the pressure relief valve 40 so that the valve 40 is protectedfrom detritus, such as dust, settling on it. Without the shroud 110, thevalve 40, when it triggers, might blast any dust from the valve 40 intothe room, which is not desirable in a surgical environment. The shroud110 also helps to prevent any unintentional disconnection of thepressure relief valve 40.

FIG. 4a shows an example pressure relief valve 40, without the shroud110 attached. In FIG. 4b , the pressure relief valve 40 has beensubstantially encased in the shroud 110. The shroud 110 in this examplesubstantially covers the length of the pressure relief valve 40, but hasa gap 112 at one end to allow the gas to escape when the pressure reliefvalve 40 triggers. In this example, the shroud 110 comprises an openended cylindrical cover inside which the valve 40 is received. Theshroud 11 may be permanently mounted, or removable.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to”.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that prior artforms part of the common general knowledge in the field of endeavour inany country in the world.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the invention and withoutdiminishing its attendant advantages. For instance, various componentsmay be repositioned as desired. It is therefore intended that suchchanges and modifications be included within the scope of the invention.Moreover, not all of the features, aspects and advantages arenecessarily required to practice the present invention. Accordingly, thescope of the present invention is intended to be defined only by theclaims that follow.

What is claimed is:
 1. A surgical gas supply system, comprising: a gassource for providing a flow of gas; and a pressure relief arrangementthat is activated in response to a system pressure above a thresholdpressure and that operates to reduce the system pressure when activated,the pressure relief arrangement comprising: a valve having a first end,a second end opposite the first end, and a length extending between thefirst and second ends; and a shroud configured to enclose a firstportion of the length of the valve such that a second portion of thelength of the valve is exposed.
 2. The surgical gas supply system ofclaim 1, wherein the system is an open surgical insufflation system. 3.The surgical gas supply system of claim 2, wherein the flow of gasprovided by the gas source is insufflation gas, and wherein the systemfurther comprises a gas diffuser that dispenses the flow of insufflationgas to an open surgical cavity to create an insufflation gas environmentin the open surgical cavity.
 4. The surgical gas supply system of claim3, wherein the pressure relief arrangement is located upstream of thegas diffuser and is positioned within a sterile portion of the system.5. The surgical gas supply system of claim 3, wherein the pressurerelief arrangement is located upstream of the gas diffuser and ispositioned outside a sterile portion of the system.
 6. The surgical gassupply system of claim 3, wherein the pressure relief arrangement islocated between the gas source and the gas diffuser.
 7. The surgical gassupply system of claim 1, further comprising a humidifier that receivesthe flow of gas from the gas source, wherein the humidifier warms andhumidifies the flow of gas.
 8. The surgical gas supply system of claim7, further comprising a filter positioned between the gas source and thehumidifier, wherein the filter is configured to filter gases prior toentry into the humidifier.
 9. The surgical gas supply system of claim 1,wherein the valve of the pressure relief arrangement is a diaphragmvalve.
 10. The surgical gas supply system of claim 1, wherein the valveof the pressure relief arrangement is a leaflet valve.
 11. The surgicalgas supply system of claim 1, wherein the valve of the pressure reliefarrangement is a ball and spring valve.
 12. The surgical gas supplysystem of claim 1, wherein the threshold pressure is no greater thanabout 12 psi.
 13. The surgical gas supply system of claim 1, wherein thethreshold pressure is no greater than about 9.5 psi.
 14. The surgicalgas supply system of claim 1, wherein the threshold pressure is nogreater than about 5 psi.
 15. The surgical gas supply system of claim 1,wherein the threshold pressure is between about 2 psi and about 9.5 psi.16. The surgical gas supply system of claim 1, wherein the gas sourcecomprises a gas bottle and a flow meter.
 17. The surgical gas supplysystem of claim 1, wherein the valve of the pressure relief arrangementvents to atmosphere.
 18. The surgical gas supply system of claim 1,wherein the shroud is removable.
 19. The surgical gas supply system ofclaim 1, wherein the shroud comprises an open ended cylindrical shape.20. The surgical gas supply system of claim 1, wherein the gas supplysystem is used to provide gases during a surgical procedure or during apre-operative procedure.
 21. A surgical gas supply system, comprising: agas source for providing a flow of gas; and a pressure reliefarrangement that is activated in response to a system pressure above athreshold pressure and that operates to reduce the system pressure whenactivated, the pressure relief arrangement comprising: a valve having afirst end, a second end opposite the first end, and a length extendingbetween the first and second ends; and a shroud configured to at leastpartially enclose the valve, the shroud comprising a first end, a secondend opposite the first end of the shroud, and a length extending betweenthe first and second ends of the shroud, the length of the shroud beingless than the length of the valve such that the second end of the shroudis spaced from the second end of the valve by a gap.